By Bernadine Healy, M.D.
The H1N1 virus, or swine flu, first brought to public attention a mere couple of weeks ago, quickly spread from its epicenter in Mexico to at least four other continents, 30 countries, and more than 5,000 people, reaching near-pandemic levels before subsiding. So far, the global outbreak of this novel strain, decoded by researchers as a mongrel mix of mostly swine, a touch of bird, and enough of human to make it jump from animal into people, has caused milder and less transmissible disease and far fewer deaths than originally feared. But it would be dangerous to assume that we are out of the woods.
Indeed, as the risk seems to abate, the public health focus must now shift promptly to the hard-to-gauge threat that this H1N1 influenza poses when flu season begins in the fall. And here our predictive abilities are no better than a coin flip. We have faced just three flu pandemics in the past century, two of which turned out not to be serious. But the pandemic of 1918 took half a million lives in the United States and, conservatively, 50 million worldwide. That virus, also an H1N1 strain, though of avian origin, first emerged in the spring like a lamb, only to return in the fall like a lion, having mutated into a fierce and deadly form. Granted, science and medicine were rather primitive at the time. But the experience is not something that public health officials can ignore. Margaret Chan, the director-general of the World Health Organization, said last week that she would rather be overprepared than have to answer questions after a deadly outbreak about why WHO did not take sufficient action.
Yet there is no certain playbook as to what constitutes the best course of action here. If we vaccinate aggressively but the virus does not reappear as a killer, for example, we could see a replay of the 1976 H1N1 swine flu fiasco. When that potential pandemic virus fizzled, the Ford administration was excoriated for overreacting with its crash immunization program, which had been recommended by the White House's health advisers and the nation's leading scientists. The president was blamed for vaccine side effects that caused paralyzing Guillain-Barré syndrome in more than 500 people and as many as 25 deaths, vastly exceeding any injury caused by the natural infection.
Despite the risk of such unforeseen consequences, there are three major actions the government needs to take now that will shape what happens in the fall.
Speed up diagnosis. Even before the swine flu outbreak was declared an emergency in late April, scientists from Mexico and Canada had already deciphered the full genome of the flu strain. But until recently, testing for the virus based on its genetic signature has been performed by a handful of government laboratories like our own Centers for Disease Control and Prevention. The centralized approach has led to backlogs that have sometimes kept patients and communities waiting in worried limbo and resulted in the closing of schools and the needless ostracizing of neighbors who were thought to be infected until the tests came back negative. There is no better illustration of the need for fast, precise diagnosis than what happened in Mexico, where more than 170 deaths were suspected within the first two weeks after the outbreak came to public attention but have turned out so far to be closer to 56. (The rest of the world combined has counted five swine flu-related deaths.) According to recent estimates, Mexico may have had more than 30,000 cases.
Even more sophisticated gene chip technology, developed with the support of the military and Homeland Security, can identify the full panel of circulating flu strains all at once and in a matter of a few hours—as well as spot any potentially dangerous mutations. Scaling such technologies up, so that testing can be widespread and much more rapid, would allow communities to tailor vaccination programs more precisely and guide the distribution of antiviral medications. Both vaccines and drugs are apt to be in short supply if things turn bad next fall.
Augment supplies of antivirals. No drug cures the flu, but antiviral agents like Tamiflu can make the illness less intense. It has no doubt been comforting to know that swine H1N1 is sensitive to this agent and that the Department of Health and Human Services has stockpiled 50 million doses as part of its national emergency preparedness efforts. Homeland Security distributed a quarter of the stockpile to areas of the country most affected by the new bug. But we have to be realistic: Because of an odd mutation, the virus that caused most flu this past season, a different and mild H1N1 virus, became unexpectedly and totally resistant to Tamiflu by year's end. The new swine strain might well follow the path of its distant cousin.
So we need backup drugs. Relenza is one, but it has not been approved for children under 7 and can be risky in asthmatics. Combining Tamiflu with older antivirals has shown some benefit. Clearly, we need newer versions of these drugs as well as other ways to fend off the virus. Consider the provocative data that vitamin D can protect against influenza of all types. The vitamin carries low cost, little or no risk, and lots of other benefits.
Settle on vaccine policy. HHS has been making preparations for a swine flu vaccine but faces many policy considerations. The first is just how many vaccines will be needed. The number under review now ranges from one vaccine, which adds swine flu protection to what's already in the mix for fall, to three vaccines—the regular seasonal vaccine already in production plus two doses of a stand-alone swine flu vaccine.
On the face of it, it's hard to believe we could marshal the resources to produce enough vaccine for a three-dose option. If universal immunization were planned, that would call for almost a billion doses of vaccine for the United States alone. Impossible.
It may be too late to groan about the nation's antiquated flu manufacturing process, which requires one to two hen's eggs to cultivate a dose of vaccine. But implementing better technology should certainly be put on the agenda as a top priority. It's clearly time to accelerate the use of new manufacturing facilities that don't rely on hens' eggs, such as the North Carolina plant just being built by Novartis.
Beyond production, we need to develop a policy for administering flu vaccines wisely. One lesson that came out of an analysis of the 1976 swine flu outbreak by Richard Neustadt and Harvey Fineberg was that the decision to manufacture a certain vaccine does not mean it should be given in a mass immunization program if the virus circulating appears to have taken a benign rather than a deadly turn.
These many critical decisions can easily be second-guessed. But all need to be made in any case, whether to prepare for swine flu or bird flu or some other pathogen that might befall us.